C70 S70 V70: Belt noise

[Clan]

Originally Posted by Luxobarge

To save actually removing the aux belt, if you have a decent tool for releasing the tension on the tensioner arm (I made one out of a bit of square-section tube) then if you take care you may be able to simply release the tension while the engine is running, just enough to stop the belt from turning. If the noise stops then, at least you know it's something on the aux belt system and if not, it's probably something on the cam belt system, which makes fixing it much more urgent. Actually, either way I'd be very wary of using the car until you've at least diagnosed the problem.

That sounds like a good way of loosing a couple of fingers when it slips 🙄

[StatusRed]

Cheers guys, I'll try and get the auxillary belt off this weekend then to at least pin it down to the cambelt or auxillary drive belt.

[Simmy]

Originally Posted by Clan

That sounds like a good way of loosing a couple of fingers when it slips 🙄

and an eye and maybe a couple of teeth

[Luxobarge]

Originally Posted by Clan

That sounds like a good way of loosing a couple of fingers when it slips ��

Why? The bar on my tension release tool is over 14" long, fingers are nowhere near anything moving, and making it slip is the whole point. I did it this way, and it was a total non-event. Remove the belt if you must, but my way took about 2 minutes to confirm a diagnosis - turned out to be shot bearings in the aircon compressor pulley.

Cheers!

[StatusRed]

Right I've taken the auxiliary belt off this morning - in the rain

And.. The noise goes away! So I think that limits it down to the auxillary belt or one of the pulleys on that belt.

Heres a video of the engine running with no auxillary belt on:

+ YouTube Video

Do we think I should next replace the tensioner and see if the noise disappears?

[ITSv40]

That sounds much better👍

I would definitely change the tensioner as it wasn't done at the belt change. Another test you could do is put the belt back on and run the engine with the ac on and off and see if there is any change - that will confirm whether the air con clutch and pulley is good.

[acshortt5]

A/c pulley runs all the time on these - electrical clutch engages compressor to pulley when switching a/c on so just pushing the button off won't eliminate a noise from the a/c pulley. It would only help to show if the noise is from within the a/c compressor.

[StatusRed]

Cheers guys, next job is to change the auxillary belt tensioner and see if the noise goes away. I'll report back once done, might be a while depending on weather conditions!